Colour matching for ink-jet prints on paper

Predicting the colour of trichromatic prints by measuring the colour of the primaries and their areas has been shown to be possible using large area textile prints. This approach has been extended to paper printing with much smaller coloured areas, in a predetermined array of squares. As before, the light reflected from the coloured areas mixed additively within the integrating sphere of a spectrophotometer. Cyan, magenta, and yellow were used, with the addition of red, green, blue, and black, to simulate the typical situation likely to arise in commercial paper ink-jet printers. Partitive colour-mixing theory was used to predict the colours, and the results compared well with those obtained by measurement. However, unwanted overlaps of the printed coloured squares caused all the measured results to be darker and of higher chroma. The reverse process, whereby the area of each colour was calculated for a given target colour, specified by its tristimulus values, was also carried out. The results were generally in agreement with the actual number of squares used to produce the target, within one square out of 16. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 18–26, 1998     

Camouflage of cotton fabrics in visible and NIR region using three selected vat dyes

To provide camouflage in near infrared (NIR) region and imitate reflectance profile of greenish leaves, cotton fabrics were dyed with three selected vat dyes, namely C.I. Vat Blue 6, C.I. Vat Yellow 2, and C.I. Vat Red 13. Reflectance curves of two types of fresh greenish leaves were measured as standard reference. Transmittance curve of vat dyes in acetone solution indicated that selected vat dyes have suitable structure to provide camouflage in NIR region. According to reflectance profiles, reflectance curve of Vat Blue 6 has more similarity with that of green leaf at the concentration of 0.85% owf (on weight of fiber) and 1.2% owf in comparison with those of C.I. Vat Yellow 2 and C.I. Vat Red 13. Cotton fabrics were dyed with different mixtures of the dyes to obtain a standard shade to reach camouflage in visible range. Chromatic values of dyed fabrics were measured (CIE1976 L*, a*, and b*) and two standard shades of the 1948 US army pattern, NATO and forest green, were obtained on cotton fabrics with ΔE_CMC < 2. Reflectance profiles of these two shades were located between the reflectance of green leaves. So, two vat dyes were introduced to camouflage dyes group, C.I. Vat Blue 6 and C.I. Vat Red 13, and used to achieve NATO green and forest green shades for first time. All dyed samples showed good fastness properties. The effect of washing and light exposure on camouflage properties of fabrics in visible and NIR region was inconsiderable. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 200–207, 2014     

Application issue of anthraquinonoid vat dyes on inherently flame-resistant fabrics

The vat dyeing process of specific fabrics with protective, inherently fire retardant properties that have a high content of aramid fibres in their composition, is presented. The research was performed on fabric samples that differ in raw material composition and aramid content. The samples were dyed in raw form (group 1) as well as after pretreatment with alkaline scouring (group 2). Measured limiting oxygen index (LOI) values showed that the selected fabrics meet the properties of inherently fire retardant fabrics. Dyeing was performed with Indanthren® Olive Green HB (manufactured by DyStar) vat dye, in exhaustion process, with a bath ratio of 1:30. The dye concentration was 3%, and sodium-hydrosulphite (Na₂S₂O₄) was used as a reducing agent. The colouristic analyses were performed based on spectrophotometric measurement and results interpretation according to CIELab system. The evaluation of primary tactile properties was performed which show an increase of smoothness and softness after scouring and dyeing. Also, wash fastness as well as light fastness tests have shown satisfactory fastness properties.     

Colour constancy based on texture similarity for natural images

Colour constancy is a classical problem in computer vision. Although there are a number of colour constancy algorithms based on different assumptions, none of them can be considered as universal. How to select or combine these available methods for different natural image characteristics is an important problem. Recent studies have shown that the texture feature is an important factor to consider when selecting the best colour constancy algorithm for a certain image. In this paper, Weibull parameterisation is used to identify the texture characteristics of colour images. According to the texture similarity, the best colour constancy method (or best combination of methods) is selected out for a specific image. The experiments were carried out on a large data set and the results show that this new approach outperforms current state‐of‐the‐art single algorithms, as well as some combined algorithms.     

Built-in lubrication on cotton fabrics

Partial cotton esters of long chain fatty acids of low degrees of substitution (D.S.<0.20) have been prepared by a variety of methods. In particular, the effects of the introduction of a stearoyl or an oleoyl group into the cellulose matrix on fabric properties, such as softness of hand and wrinkle recovery, have been studied. Attempts have been made to compare fabric properties of partial esters of like D.S. prepared by various methods of esterification and effect of a chemically attached alkanoyl group with effect of the same group deposited or adsorbed on the surface of the cotton fabric. Consideration has been given to the size of the alkyl group, its orientation on the surface of the fiber and its hydrophobicity. Data indicate that resistance to abtasion of cottons chemically modified with long chain alkyl groups is reduced whenever the finished fabric has high dry wrinkle recovery. High dry wrinkle recovery is obtained after esterification of cotton in nonaqueous media. Improvement in resistance to abrasion is pronounced when the alkyl group has not been chemically combined with the cellulose matrix in the absence of water, and usually is obtained when the finished cottons possess only high wet wrinkle recovery. One of eight papers being published from the Symposium “Surface Active Agents in the Textile Industry,” presented at the AOCS Meeting, New Orleans, April 1970. So. Utiliz. Res. Dev. Div., ARS, USDA.     

Retardation of vat dye uptake on cotton by phosphonates

Cotton dyeing with Cibanone Brilliant Yellow GMD was found to be considerably retarded by the presence of phosphonates. The extent of retardation was proportional to the number of phosphonic acid groups present in the molecule of the phosphonate.     

Flame-resistant polyester/cotton fabrics

New experimental results are reported for the modification of 50/50 polyester/cotton blend fabrics made from bromine-free and bromine-containing polyester with a reactive flame retardant compound of high phosphorus content. Reaction of the cotton in the blend with methyl-phosphonic diamide yields modified fabrics in which flame resistance is attained without impairment of fabric hand. The level of flame resistance depends on the amount of insolubilized phosphorus in the treated fabric, but the hand is essentially unchanged even for fabrics of high phosphorus content which pass the vertical test of DOC-FF-3-71. The results of this work provide a basis for improved definitions of future approaches to the development of flame resistant polyester/cotton blend fabrics.     

Colour preference for Taiwanese floral pattern fabrics

A psychophysical experiment was carried out to investigate factors affecting colour preference for Taiwanese floral pattern fabrics, as a case study of object colour preference. A total of 175 test images of Taiwanese fabrics were used as the stimuli presented on a calibrated computer display. The images were generated on the basis of 5 existing Taiwanese fabrics, each manipulated into 35 images by changing the fabric colour. The 35 colours were selected to cover the most frequently used colours for existing Taiwanese fabrics. The 175 test images were assessed by 76 Taiwanese observers in terms of 9 semantic scales, including Taiwanese style/non‐Taiwanese style, Japanese style/non‐Japanese style, splendid/plain, traditional/modern, active/passive, warm/cool, heavy/light, like/dislike and harmonious/disharmonious. The experimental results reveal two underlying factors: “Splendidness” and “Harmony.” The like/dislike response was found to highly correlate with harmonious/disharmonious, but have poor correlation with Taiwanese style/non‐Taiwanese style. The study also reveals several factors affecting colour preference for Taiwanese fabrics, including the interaction effect of colour and pattern, observer's general liking for the object, and the effect of user experience. These findings can help develop a more robust, comprehensive theory of object colour preference. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 43–55, 2016     

Colour gamut of natural dyes on cotton yarns

Cotton fibres were dyed using various natural dyes alone and in combination to yield six basic shades: blue, yellow, red, black, green and fawn. These dyed fibres were then blended in various proportions along with undyed cotton fibres and spun on a rotor-spinning machine to produce 204 coloured yarns. The fastness properties of the six basic shades were determined. The L * a * b * and L * C * h values of the yarns having 50% dyed fibre and 50% undyed cotton fibre was also determined. The values were plotted to obtain the colour gamut of natural dyes on cotton yarns.     

Durable antimicrobial finish of cotton fabrics

Cotton fabrics were treated with Biopag, which does not have any functional groups that are reactive toward cellulose, using crosslinking agents or a binder, for the purpose of imparting a durable antimicrobial finish. In this respect, it was found that the crosslinking agents were more effective than the binder. It was confirmed by FT‐IR that the characteristic split peaks of Biopag were still seen even after repeated launderings. The crosslinking agents deteriorated the whiteness and tensile strength of the Biopag‐treated cotton fabrics, while the wrinkle recovery angles (WRAs) were significantly improved. The one‐step padding of Biopag and the crosslinking agent was found to be superior to the two‐step padding method in which Biopag padding was followed by padding of crosslinking agent in respect of WRA, whereas the whiteness and tensile strength were vice versa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Dry action of Trichoderma reesei cellulases on cotton fabrics

Following treatment with Trichoderma reesei cellulases, the mechanical properties of cotton fabrics were measured to assess the effect of adsorbed enzymes. The ability of adsorbed cellulases to act as anchors for further wet finishing processes was studied. Dried fabric samples, after 105 days under usual storage conditions, showed neither significant strength loss, nor any changes in the degree of polymerisation. After five months of storage, the enzymes were still found to be active. The adsorption of T reesei cellulases produced an increase in staining levels after dyeing with an acid dye, but washing fastness was poor. Washing with soap under alkaline conditions removed proteins almost completely. Adsorption of T reesei cellulases is reversible and desorption increases from pH 5 to pH 10. Because of the protein desorption under usual alkaline washing conditions, no practical application of adsorbed cellulases for further finishing processes is suggested and more work is required.     

Surface treatment of cotton fabrics with chitosan

Antibacterial activities of cotton and polyester/cotton fabrics treated with chitosan or chitosan/DMDHEU have been investigated. The washing durability properties of the aforementioned fabrics were also studied. Another group of fabric samples produced from mature and immature cotton fibres were dyed with reactive dyes and the colour yields and colour differences of the dyed fabrics assessed. The surfaces of the treated and untreated cotton fabrics were observed by scanning electron microscopy to compare the morphology.     

Effect of chemical modification of cotton fabrics on dyeing properties

The presented research deals with modifying the chemical structure of the cellulosic cotton fabrics by introducing amino groups as new active centers. The properties of the resulting aminated cotton, dimethylaminoethyl (DMAE)‐cotton, are evaluated and discussed by studying the dyeability, light fastness characteristics, and fading kinetics. The goal of this study was achieved. The modification succeeded in saving energy by decreasing both the dyeing time and temperature, and the dyeability and light fastness characteristics were improved. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1897–1903, 2002     

Influence of pregrafting cotton fabrics on kinetics of DMEU finishing

Cotton fabrics were pregrafted with a mixture of N-methylolacrylamide and methacrylic acid at mixing molar ratio of 4/6. The influence of pregrafting on the kinetics of finishing with 1,3-dimethylolethylene urea was studied. The results shows that pregrafting can increase the rate constants. Values of E_a ΔH^*, ΔS^*, and ΔG^* suggest that the pregrafting of cotton fabric not only affects the reaction action state, but also is beneficial for the reaction between cellulose and the finishing agent. © 1996 John Wiley & Sons, Inc.     

Modeling the deposition of fluorescent whitening agents on cotton fabrics

The adsorption of two widely used fluorescent whitening agents (FWAs) on unbrightened cotton fabrics has been investigated as a function of temperature, hardness of the wash liquor, initial concentration of FWA in solution, and fabric to wash liquor ratio. Sorption efficiencies of FWAs have been studied using a UV spectrophotometry technique. A mechanistic model has been developed to describe the dissolution process of FWAs, convective mass transport into the fabrics, diffusion in the stagnant layer to the fabrics' surface, and adsorption of FWAs on cotton fabrics. Dual porosity of the fabrics (inter‐yarn and intra‐yarn porosity) has been considered by allowing two different regions (outer and inner areas of the cotton fabrics) where FWAs molecules can diffuse and adsorb. Good agreement between experimental and predicted whiteness benefit by the proposed mathematical model has been observed for the range of variables considered. © The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of 2017 American Institute of Chemical Engineers AIChE J, 64: 1305–1316, 2018     

Thermoanalytical characteristics of durable press treated cotton fabrics

Thermoanalytical characteristics of chemically treated cotton fabric often appear similar to those of untreated cotton. The overwhelming amount of cotton cellulose versus the small quantities of finishing chemicals present can mask many features contributed by reactant. The current work is an initial attempt to detect and differentiate among a variety of durable press finishes. They include three N-methylol reactants, and four polycarboxylic acids with two alkali metal salts of phosphorus-containing acids used to catalyze their reaction with cellulose. Differential scanning calorimetric and thermogravimetric techniques were employed under dynamic nitrogen conditions. Changes in residue, rate of weight loss, peak intensity, and peak temperature were observed and varied with reactant, catalyst used, and washing. The ability to distinguish among polycarboxylic acids, catalysts, and/or other formaldehyde-based reactants is of value to the textile chemist. With these preliminary results, we may soon offer a new means of finish identification. © 1993 John Wiley & Sons, Inc.

1 This article is a US Goverment work and, as such, is in the public domain in the United States of America.

     

Antimicrobial activity of cotton fabrics containing immobilized enzymes

Immobilization of α‐amylase, alkaline pectinase, and laccase enzymes onto ester‐crosslinked as well as Cu‐chelated cotton fabrics were carried out. Factors affecting the extent of enzyme‐loading and retention activities of immobilized enzymes were studied. Proper conditions for attaining higher extent of fixation along with better retained activity were studied. The degree of antimicrobial activity of treated fabric samples against gram‐negative and gram‐positive bacteria, filamentous, and nonfilamentous fungi were evaluated. The antimicrobial activity is determined by the type of substrate, i.e., Cu‐chelated > ester‐crosslinked and activated cotton substrate, and the nature of immobilized enzyme, i.e., alkaline pectinase > α‐amylase > laccase, irrespective of the used microorganism. The antimicrobial activities of the treated fabrics are completely maintained after laundering at least ten consecutive wash cycles. Further consecutive wash cycles, i.e., 20 or 30 cycles, has practically negative impact on the retained antimicrobial efficacy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1754–1761, 2007